Charles, I have seen this before during an immunity test. It happened on a commercial product (not ours) on the IF and LO circuitry during a CE Mark test. Specifically, it happened with the feedback trace of an LO PLL used for the IF. The PLL circuitry was unshielded and a small band of frequencies caused a mixing product which totally confused the receiver. The fix was to shield the PLL to prevent the susceptibility. The trace was later buried in the PWB to shield it. Philip Ross Wellington Mgr. Signal Integrity & EMI L-3 Communications CSW
-----Original Message----- From: Grasso, Charles [mailto:[email protected]] Sent: Tuesday, October 29, 2002 4:48 PM To: [email protected] Subject: Question on Receiver EMI testing.. Group, A hypothetical question for you... Should a receiver mounted on an antenna be "lit up" during an emissions test? The receiver down-converts the received signal?? Thanking you all in advance.. Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Email: [email protected]; <mailto:[email protected]; %20> Email Alternate: [email protected] <mailto:[email protected]>
